Having brake shaking

M

mendozer

Member
A while ago after putting in new brake pads and rotors I started having pulling when braking so I took it into a shop and they suggested caliper was stuck. It had pulled to the right before so i thought ok sure. They were Powerstops I added when I did my TBU. So i get the NAPA ones, pop those on. Pulling was gone, great.
Vibrating started slowly then got worse. So then I take rotors off to a machine shop who happens to be one of the few in the area to turn them. Despite being brand new and a good brand, they were off a bit. So i pop those back on, smooth, great. Vibrating starts again and esp over 40 mph. So now i'm thinking shoot did my pads get uneven wear from the rotors? I figure they would have leveled out by now.
Back when the shop first gave me the free brake consult they suggested changing my brake lines. I have The Centric/Stoptech stainless lines again installed with my TBU back in '17. So they're not nearly as old as what the OEM lines were on there for what 15 years. But brake lines causing wobble? Maybe if there was gunk in there but why not just blow it out with compressed air vs replace?

Just want to get feedback before I go spending money on brake lines.
 
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Did you bed in the new pads to the new rotors?
It is a process described a lot in internet.
Sure calipers could contribute. Especially if pins are not well lubed , calipers are rusty etc.
I too have difficulty with brake lines contributing.
If brake lines have inner lining and outer sheathing -I imagine a defective lining could become collapsed and affect brake fluid flow when brake pedal pushed? But I do not think this likely?
How about your A-arm bushings, ball joints?
Could new rotors have become contaminated with grease on inner surfaces? Now that pad is contaminated also? The dust shield hides the rotor inner surface when all assembled so sluthing it will require disassembly.
 
I have heard of the OEM rubber flex lines going bad and essentially collapsing internally... I guess the aftermarket lines can have issues. Who knows what the lifespan of those lines would be. 8 years have passed. Might be worth getting another set. However, that is up to you. :-)
 
Hungryhawk said:
Did you bed in the new pads to the new rotors?
It is a process described a lot in internet.
Sure calipers could contribute. Especially if pins are not well lubed , calipers are rusty etc.
I too have difficulty with brake lines contributing.
If brake lines have inner lining and outer sheathing -I imagine a defective lining could become collapsed and affect brake fluid flow when brake pedal pushed? But I do not think this likely?
How about your A-arm bushings, ball joints?
Could new rotors have become contaminated with grease on inner surfaces? Now that pad is contaminated also? The dust shield hides the rotor inner surface when all assembled so sluthing it will require disassembly.
Click to expand...

Yes i bedded them on the new rotors...before i knew they weren't perfectly flat. so they were bedded to the ever so slightly off rotors. After turning the rotors i did not bed anything again since the pads had already done it. My bushings all over are shot. I have all new suspension bushings to put on when i get a chance. Why would suspension bushings cause vibration only when braking? wouldn't that be all the time like a wheel being off balance? Did not notice contamination of anything
 
brillo_76 said:
I have heard of the OEM rubber flex lines going bad and essentially collapsing internally... I guess the aftermarket lines can have issues. Who knows what the lifespan of those lines would be. 8 years have passed. Might be worth getting another set. However, that is up to you. :-)
Click to expand...

sure i mean anything's possible. i'm trying to rationalize what to go for vs just throwing parts at it
 
I believe the bedding process evenly transfers pad material to rotor. The brake pad/caliper creates friction with the pad material embedded in the rotor surface. This friction is the way brakes work. Turning (removing) metal from rotors to resurface true (no runout or warp) will remove the pad material in the rotor along with rotor steel. I do not think that one surface not bedded and 3 surfaces bedded could explain your vibration.
I am definately out of my experience level here-
I personally replace factory pads on factory rotors without surfacing/turning rotors everytime because I always use same pads with same material everytime-so brakes are already mostly bedded. I use a simple bed in and not the full multi braking cycles with increasing intensity like a proper bed in job. Driving I avoid hot hard stops so I rarely get an uneven pad build up spot on rotors which can cause pulsating when braking.
I hope you can solve the problem soon, so you can stop wrenching and do more driving to fun places.
 
well by now 2 months later (after i returned the rotors), i would imagine the rotors have been bedded just by driving use unless you can convince me to bed them again
 
Thinking outside the box sometimes, start from scratch or near.
Liberally clean rotors both sides and pads with brakeklean do complete rebed. Worked for me a time or two.
Time or two I've used heavy cut scotchbrite type disc on 4" grinder with brakeklean clean rotors and pads
rebed procedure.

It's about even coat of pad material both sides of rotor.
 
Pretty easy to check what Endless implies above.
Rotate your tires front X back. See if that has an effect.
 
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96RedRunner said:
Thinking outside the box sometimes, start from scratch or near.
Liberally clean rotors both sides and pads with brakeklean do complete rebed. Worked for me a time or two.
Time or two I've used heavy cut scotchbrite type disc on 4" grinder with brakeklean clean rotors and pads
rebed procedure.

It's about even coat of pad material both sides of rotor.
Click to expand...
If you catch it before it gets bad, you can basically just re-bed without doing any extra work. You have to start that with a very light application of the brakes to get the uneven layer off first.

Depending on pad material and driving style/conditions, the transfer layer from bedding can wear off, which then can cause brake pulsing after even just one hard brake application.

A thing you can do all the time is avoid coming to a complete stop after any hard braking events - try to leave one car length or so to creep after coming to a near stop to avoid holding the pads in one location on the rotor when hot.

-Charlie
 
yeah that's basically how i always stop with a little let off to find a new spot to softly clamp pads onto rotors vs leaving on the first location.
 
phattyduck said:
If you catch it before it gets bad, -Charlie
Click to expand...

Indeed, have to agree and do the above. Garden hose good nozzle flooding cold calipers & pads
has solved minor pulsing start simple progress as needed.
My S5 has electric park brake not a good idea to set it hot. :)
 
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ok i just did an inspection and found that the passenger side inner side of the wheel rim had some kind of liquid film that the driver side didn't. Interesting. The driver side brake retaining clip got kind of messed up (the W thing for the TBU). It looks like parts of it touched the rotor bc metal was ground off and it was bent weird. Both rotors had darker lines in the middle of where the pads would sit. I just cleaned both side rotors and pads and gave a good scuffing of a superfine grey scotch brite pad. Then i drove around to bed in again. And right away i can feel the vibration. It's not pulsing through the pedal i don't think just a vehicle shake and it is pretty rhythmic bum-bum-bum-bum and when slowing down to 10 mph i can kind of hear the same alternating (albeit slower) whining on-off-on off. Cant tell which side it comes from.

So....No fix yet. And honestly it might feel even stronger of a vibration now.
 
I just ended up taking it to a shop today that works on Japanese cars and right off the bat The guy said he wouldn't fix anything for me because I don't have the stock brakes and rotors but instead the tundras. But then he called me and told me that yes, the rotor is warped despite the fact that it's a pretty brand new rotor. He also said something about the calipers not releasing all the way up and that it's something he's read about about these tundra swaps with the Master cylinder. But I've had them in there for about a decade so I'm not sure I'm buying that
 
Did a fluid flush and put OEM rotors on. In the process I snapped one of the "W" clips on the driver side. It was damaged from I guess the vibration beforehand bc the metal was ground thin from the rotor. How important is this thing? It has nothing to do with pads staying in the grooves bc the pass through pins do that
 
mendozer said:
Did a fluid flush and put OEM rotors on. In the process I snapped one of the "W" clips on the driver side. It was damaged from I guess the vibration beforehand bc the metal was ground thin from the rotor. How important is this thing? It has nothing to do with pads staying in the grooves bc the pass through pins do that
Click to expand...

If the "W" clip you're referring too is what I think it is I would get one to replace it, it's for reducing the drag of the brake pads on the rotor by applying outward pressure on the brake pads, if you don't replace it you risk unwanted brake drag.
 
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Can't attach the photo but the passenger wheel seems to have fluid on it spinning out from the inside. Makes me think brake fluid also because when holding at a red light I feel the calipers losing grip and the car creaks and inches forward. So that's my guess, leak from somewhere
 
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